This invention relates to a container which has been deed particularly though not necessarily solely for the transport of fresh produce such as vegetables, fruit, fish and meat. It is envisaged however that other items such as semiconductors and the like could also be transported in the containers of the invention.
Accurate temperature control during the transportation of perishable products in a container is important in order to maximise their storage or shelf life. Distribution of temperature controlled air within a transport vehicle or storage facility is an important feature of the refrigeration system.
The smaller the transport or storage container the greater its surface area is in relation to its volume. Heat is gained by transfer through the walls of the transport container. The smaller the container, the greater percentage of its cargo volume that is in contact with or in close proximity to the containers"" walls (the surface area) thus making it harder to refrigerate.
The means by which temperature controlled air is circulated within a transport container is vitally important in order to avoid hot spots developing in the perishable cargo. The most common methods of air circulation used in refrigerated transport systems is either bottom air delivery or top air delivery into the container.
Typically the refrigeration plant is mounted at one end of the transport vehicle. Air is cycled through heat transfer coils, then passes into a single air duct entering the cargo area, either along the containers"" floor or roof, and returns through a single inlet, also located at the machinery plant end of the transport vehicle, but usually at the opposite side to the outlet duct. For example, in a refrigerated sea container, if the outlet duct is positioned near the floor of the cargo area then the inlet duct would be positioned near the roof of the cargo area. The air distribution cycle is continuous during the refrigeration process.
For refrigerated trucks and sea containers this method is considered by operators to be satisfactory. Variations in perishable products temperature measured at different locations within transport vehicles are commonly acknowledged but generally within acceptable limits for the trade.
Applying the same air distribution system to smaller containers, (the size of a loaded pallet) has not been successful due to a larger percentage of the perishable cargoes"" volume being in contact or in close with, or close proximity to the containers"" walls.
It is therefore an object of the present invention to provide a container which will go at least some way towards obviating or minimising the foregoing disadvantages in a simple yet effective manner or which will at least provide the public with a useful choice.
Accordingly in one aspect the invention consists in a container comprising a base, a plurality of side walls and a top, at least some of the side walls having ducts therein through which gas can flow.
In a further aspect the invention consists in a container comprising a base, a plurality of side walls and a top, there being ducts within at least some side walls, and a gas moving device arranged to direct gas through said ducts.
In a still further aspect the invention consists in a method of maintaining the temperature of or cooling a container having a top, a bottom, and a plurality of side walls comprising the steps of directing a flow of gas at the desired temperature up or down through one or more sides of the container and allowing the gas to return down or up through other side walls, or through the body of the container.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.